The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines combust an air and fuel mixture to generate drive torque. The combustion process generates exhaust gas that is exhausted from the engine to the atmosphere. The exhaust gas contains nitrogen oxides (NOx), carbon dioxide (CO2), carbon monoxide (CO) and particulates. An after-treatment system treats the exhaust gas to reduce emissions before the exhaust gas is released to atmosphere. In an exemplary after-treatment system, a dosing system injects a dosing agent (e.g., urea) into the exhaust gas upstream from a selective catalytic reduction (SCR) system. Urea breaks down to form ammonia (NH3) through thermal decomposition. NH3 is the reductant that reacts with NOx over the catalyst in the SCR system.